A comparitive evaluation of life span of nickel titanium rotary file system in continuous motion with reciprocating file system in curved root canals : An in vitro study.

Dr Azhar malik; Dr. Sumit Sabharwal; Dr Aina Kumar; Dr. Annil Dhingra; Dr Anshdeep Singh; Dr. Marilia Marceliano–Alves

Volume : VI, Issue : VI, June - 2017

A comparitive evaluation of life span of nickel titanium rotary file system in continuous motion with reciprocating file system in curved root canals : An in vitro study.

Dr Azhar Malik, Dr. Sumit Sabharwal, Dr Aina Kumar, Dr. Annil Dhingra, Dr Anshdeep Singh, Dr. Marilia Marceliano Alves

Abstract :

Aim: To evaluate the fracture resistance of Ni–Ti files in continuous and reciprocating motion in curved mesial canals of human permanent mandibular molars. Material and methods: Forty human permanent mandibular molars with mature apices extracted for Periodontic reasons were selected for this study. They were stored at 4�C in 0.1% Thymol solution and used within 1 month after extraction. Endodontic access was obtained and a size 10 K– file was introduced to determine the working length of the root canal. After the completion of preparation, the teeth were randomly distributed into two groups. Group A (Continuous Motion) – Complete cleaning and shaping was done with One Shape� (Micro Mega, France) file in continuous motion. The file was reused in another tooth, until the file fractured. This was repeated until all the 5 files were fractured in the group. Group B (Reciprocating Motion) – Same procedure for cleaning and shaping was done. The file was reused in another tooth, until the file got separated / distorted. This was repeated until all the 5 files were separated in the group. The time needed for the complete preparation was noted for both the groups. Evaluation of fractured instrument was then subjected to Scanning Electron Microscope Evaluation. Results: Average number of canals that can be prepared successfully without fracture by a single One Shape� file in continuous motion was found to be 5.4 canals. Similarly on an average 3.6 canals can be prepared successfully in reciprocating motion without fracture using One Shape� file. Average time required for preparation of one canal in continuous motion is 223 seconds and that in reciprocating motion is 344 using One Shape�.This analysis was confirmed by comparison of two groups by T test. The p value calculated for the number of canals prepared was 0.037, was statistically significant (<0.05) and showed that significantly more number of canals can be prepared using One Shape� files in continuous motion. Conclusion: Single One Shape� file can be safely used to the working length of curved canals at least 5 times under continuous motion without any help of other files. While One Shape� can be used safely in reciprocating motion in at least 3 canals. Preparation in reciprocating motion with only one One Shape� file was much slower than root canal instrumentation in continuous motion.